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Kernel_task process takes 700% of my cpu when I plug in my external monitor

Hello,


this afternoon I started getting this really annoying issue on my MBP 16" (2019). For the past year, I've always used my laptop with an external monitor using an USB-C to Display Port cable. Never got a single issue. Today I plugged in my display port cable like any other day and after a few minutes, my MBP became pretty much unusable due to kernel_task using over 700% of my cpu. I plugged out the cable and it came back to normal in a matter of seconds.

My MBP is fairly new (less than one year old) and on top of that, I got it cleaned from all the internal dust less than 3 weeks ago. I never had overheating issues. In fact, even though kernel_task completely takes over my CPU, the temperature doesn't even get that high (roughly 60-65 degrees Celsius).


I've tried the following but nothing helped so far:

  • Updating to the latest BigSur version (11.3 as of today)
  • resetting SMC and PRAM
  • Cleaned my SSD from about 50 GB of useless files and apps
  • Set the fan to run to the maximum in order to get the temperature even lower (even under 60 degrees Celsius, the issue persists)


Any help would be greatly appreciated. I'll keep this thread updated in case I manage to fix it myself.





MacBook Pro 16″, macOS 11.3

Posted on May 3, 2021 10:51 AM

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Question marked as Top-ranking reply

Posted on May 4, 2021 10:26 AM

Hey nullRouted,


If we understand correctly, kernel_task uses over 700% when you connect an external display. Try booting using safe mode and see if the issue persists there. Even though there is a chance that you've tried these steps already, we would recommend you follow every step and let us know if the issue persists.


Get help with video issues on external displays connected to your Mac


Start up your Mac in safe mode


Please don't hesitate to let us know if the steps resolved your issue or if you need additional assistance.


Thank you for using Apple Support Communities. Have a good one.

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6 replies
Question marked as Top-ranking reply

May 4, 2021 10:26 AM in response to nullRouted

Hey nullRouted,


If we understand correctly, kernel_task uses over 700% when you connect an external display. Try booting using safe mode and see if the issue persists there. Even though there is a chance that you've tried these steps already, we would recommend you follow every step and let us know if the issue persists.


Get help with video issues on external displays connected to your Mac


Start up your Mac in safe mode


Please don't hesitate to let us know if the steps resolved your issue or if you need additional assistance.


Thank you for using Apple Support Communities. Have a good one.

May 4, 2021 10:32 AM in response to mario49

Hi,


yes, I tried doing this a few hours ago but it didn't work either. The only thing I can do is unplugging the cable, waiting 30-40 seconds, plug it back in and wait until the issue comes back and repeat the process.

The issue comes back at very random intervals of time, sometimes after 10-15 minutes of usage and other times after hours of usage. I can't really track what's the cause.

Kernel_task process takes 700% of my cpu when I plug in my external monitor

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